DuH told me to, so I smiled and said "sure."
(Warning: when I post from this computer the paragraphs disappear. If so, I will come back and edit.)
BG:
I have been on this board for about a year and have really learned a lot about setting healthy boundaries. I have set them with my FOO and found that to be helpful. However, this is about the IL's. I have the typical MIL we read about on this board. I have been married to DuH for 4 years, together for 5.
Everything was fine and dandy until I started standing up for myself and demanding space. Then all hell broke loose with them! MIL: Plays the "I'm a grandmother and I have RIGHTS." Has sent DuH texts saying I'm brainwashing him. I'm keeping him from his real family. Coming from the woman that constatly ran away with strange men and abandoned her kids and husband (more than 5 x's), this is dumb!
EX: "...And your sisters that thought the world of you are just saddened that you have just totally ignored them this is all so sad. I am trtidng to be very upfront and kind about this I think you shouls at least talk to your sisrers. I am jist mom and I know things should not be this way...I hope onedaythat you see what is going on and wake up...I love you...mom" (all spelling is hers. The sister she is referring to is 22. 
Sorry he got married and has kids and wife now?!
Anyway, this sister has been with her BF for about 7 years. He is 24, I believe. She has been drinking and partying since HS. This guy uses her. Broke up with her when she had no job and car and ran around with other women (he has repeatedly cheated on her). He came back to her when she got a job and car. But whatever, she has asked for guidance, we all have given it to her...but she chooses to be with him. MIL has gotten voicemails from her IL's saying that they didn't want her at their house because they have young children and they don't appreciate her walking around naked or having sex with their son in their home. To keep the little ***** home. (yes this was when she was in HS). MIL was mad and told DuH that she wished he was there because they wouldn't be messing with her then and SIL agreed.
On to the current issue. SIL is 22 and still with this guy. A few nights ago she text him saying, "My FFIL went off on me and yelled at me. :( I wish you were here.." DuH responded with " I wish I was there too.." "It's ok, I"m fine. No big deal. But you should come home." End of exchange...
This creeped me out. I told DuH she is an adult making her own choices. If she has issues with her IL's then she should be turning to HER DuF and he needs to start setting boundaries with his extended family. His view is "she's my LITTLE sister." I pointed out the he is the head of OUR family and the protector of OUR KIDS. He is not supposed to assume that role for his adult sister. Second, he is home FFS! His home is here with his wife and kids, in a state 22 hours away from the IL's. And he needs to put an end to this shit. He responded with, "all you talk about is boudaries. My family doesn't work that way. There's no need for boundaries. Why don't you post this on your internet board..."